Signaling-circuit for telephone-exchanges



(No Model.)

G. E. SORIBNER.

SIGN ALI NG CIRCUIT FOR TELEPHONE EXOHANGE-S.

' No. 333,167. -Patented Dec. 29, 1885.

N, PETERS. PholwLfllmgnphor. Washingion. I) Q UNIT D. STATES PATENT OFFICE. 1

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS.

SIGNALING-CIRCUIT FOR TELEPHONE-EXCHANGES.

SPECIFICATION forming part of Letters Patent No. 333,167, dated December 29,1885.

Application filed J une 11, 1883. Renewed October 22, 1885. Serial No. 180,579. (No model.)

To all whom it may concern.-

Be it known that I, CHARLES E. SORIBNER,

a citizen of the United States, residing at Ohicago,in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Signaling Circuits for Tele phone-Exchanges, (Case 15,)of which the following is a full, clear. concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention is an improved system of circuits for signaling between the terminal stations and the central office.

In the systems now in common use a subscriber signals the central officefirst to indicate that he wishes to communicate some order, and then the attendant switchman connects the subscribers telephone-line with the telephone of the listening operator, who receives the subscribers particular order and informs the switchman thereof. By the use of my system the preliminary call to gain the attention of the central office is dispensed with, and a subscriber is enabled to communicate his particular order immediately on taking hishandtelephone from the switch.

In the drawings, Figure 1 shows my system of circuits in connection with the American District Telegraph. In Fig. 2 my system is shown independent of the American district system. a

,A, Fig. 1, is a common return-wire which passes through American district call-boxes 1, 2, and 3, a single box being placed at each subscribers office or anywhere in the circuit. A, Fig. 2, is a common return-wire, which in like manner passes through a group of terminal stations of subscribers. No American district boxes are shown. They may be used or not, as heretofore, for signaling, but are of no use in connection with my telephone-signaling circuits as such.

By the use of condensers (shown in Fig.1 and hereinafter more particularly described) the common return-wire may be used for telephone and American district purposes at the same time.

a is a trunk line connecting the central oftlce of two exchanges.

to is a line connecting the return-wires A and A of the two exchanges.

b c d and b c d are individual telephonelines.

The outfits of subscribers connected with lines b and b are shown in detail.

It will be seen that subscribers connected with the system shown in Fig. 1 may be connected with those of the system in Fig. 2.

I will now describe in detail the system shown in Fig. 1. Beginning at the central office and tracing the circuit from the cut-out or connecting plate on the switch-board to the subscribers oflice,the wire b is found 0on nected to the leverf of the automatic switch, which is normallyin position shown when the telephone-receiver is hung upon the hook. We trace the circuit from the lever of the switch through the points shown in contact by the line 9 through the call-bell, thence to a branch wire, h, and the key 2' to the key It, and thence by line Zto the common returnwire A, and thence to battery m at central office. Now, suppose that the central office wishes to call the subscriber connected by line b. The signal is made by inserting plug a in the connecting-plate e of line b. The battery m thus has its circuit completed through the individual wire b to the call-bell of the subscriber and through the common returnwire A, thus ringing the call-bell. The subscriber connected by wire b communicates with the central office through his telephonereceiver, which he must remove from the lever f, thus changing the circuit of the individual wire b from the call-bell to his induction coil, transmitter, and receiving telephones, and .thence to ground in the usual manner. The battery-plug it having been removed from connecting-plate e, the circuit of wire b is completed through said plate to the wire 0, leading to the listening operators telephone p, and to ground. Thus the subscriber is enabled to speak directly to the operator at the listening operators telephone 10, and thus communicate his wants. Let us suppose that the subscriber connected with the line b wishes to communicate with the subscriber connected with wire (I. He first removes his receiving telephone from the lever f and speaks directly to the operator at the listening-telephone 19, giving the name of the party with whom he wishes to communicate, in this case the one connected with line d. The listen- 5 ing operator repeats his order to a switch man,

who calls up the desired subscriber by inserting the plug a in plate q, thus ringing thebell at subscribers ofiice. He then connects the lines b and d together by means of a connect-' ing cord, )7. The connecting cord 1'? is branched through an annunciator-magnet, its shutter, and armature to ground, so that when the subscribers have finished their conversation either can signal a disconnection by means of the magneto-box or local battery at either of their stations. This annunciator-magnet, connected with the cord M", will thus drop the shutter and disconnect the ground-connection from the magnet, and through the changing :o', of the position of the shutter will connect the individual wires through a clearing-out operators telephone, s, and thus bring both of the subscribers connected by cord rr into com munication with the clearing-out operator :5 through the medium of the telephone 8.

I have shown in the circuit of the common return-wire A American district call-boxes 1, 2, and 3, and at the central oflice a battery, t, is in the circuit of a relay. The relay is in gopractice arranged to operate as a register by means of local connections, and a signal made at either of the boxes 1, 2, and 3 is thus recorded at the register.

When American district boxes are used in 5 jc'onnection with my system, I place condensers w, w, 1 and 2 at the central office, as shown. Each condenser is connected with the line, so as to leave the circuit of the individual wire open to battery-circuits, but closed to vibrata,o' ing currentssuch as currents induced by the voice. Thus the boxes 1, 2, and 3 are not short-circuited, as they would be in case the individual wires were connected directly to the wire w. Heretofore the subscribersindividual lines have been grouped together and each group connected by a common line through the listening operators telephone to ground. The several lines of a group were connected at their terminal stations through a call -'bell and to ground. It is evident that only a limited number say from twenty to thirty 1ines-could be grouped together and be operative, as the telephone of the listening op erator would only receive its proportion of the current sent in by a given subscriber. The portion of the current not passing through the operators telephone would be divided and escape to ground at the other terminal stations of the group.

The individual lines in my system, instead of normally connecting with the ground at the terminal stations, are connected with the common return-wire, which serves for signaling, but which is never connected with the ground. Therefore the number of lines that may be connected with a single operators telephone is not limited by the escape of the voice-current over other wires of the group.

I claim- 1. A group of individual telephone-lines, in combination with a listening operators telephone, a common return-wire normally open at the central oifice, and a calling-battery in the circuit of the return-wire and a switch at each subscribers oifice, substantially as and for the purpose specified.

2. The combination, with a signal-circuit, including one or more signal-boxes, of the battery ,t, the relay or receiving-instrument, and branch circuits from said signal-circuit to ground, each branch containing a condenser and a telephone included in the common ground-wire, substantially as and for the purpose specified.

3. The combination, with the signal-circuit,

including the signal-boxes, of a branch cir-..

cuit from said signal-circuit to ground at the central station, condensers, one in each branch circuit, the common ground wire to which,

the branch circuits are connected, the telephone in said common ground wire,and switchingapparatus for connecting and discon necting the ditl'erent branch circuits from the signalcircuit. 1 4. The signal-circuit A, including signalboxes 1 2 3 and battery It, and the signal-receiving instrument, in combination with the telephone-circuits radiating from said signal-circuit to ground,each branch circuit containing acondenserand telephonic apparatus,whereby telephonic communication may be had from one point to another over said signal-circuit without impairing the integrity of the signalcircuit.

'5. A signal-circuit including signal-boxes, in combination with branch circuits from said signal-circuit through telephones and con densers to ground and switches to disconnect any branch circuit from the signal-circuit.

In witness whereof I hereunto subscribe my name this 2d day of June, A. D. 1883.

CHARLES E. SCRIBNER. Witnesses:

. PAUL A. STALEY,

G. P. BARTON.

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